The present invention relates to telecommunications and more particularly to packet switched networking systems capable of carrying voice traffic.
Recent legislative changes in the United States have promoted competition in the telecommunication industry and spurred demand for new services at lower prices. These trends are pressuring major telecommunications carriers to increase capacity while reducing the cost of providing service. Consequently, major carriers around the world are looking to packet technologies, such as Internet Protocol (IP), frame relay, and Asynchronous Transfer Mode (ATM), to replace circuit-switched technologies in the Public Switched Telephone Network (PSTN) for providing voice capability. In addition, IP, frame relay, ATM, and other packet-based technologies offer narrow-band and broad-band services to selected customers on the same network, providing the same platform for integrated voice, data, and video services from low bandwidth to very high bandwidths.
Over the decades, however, major voice carriers have invested heavily in developing a Signaling System 7 (SS7) signaling and switching infrastructure to offer reliable telephone service. This infrastructure includes countless systems for billing, provisioning, maintenance, and databases that are compatible only with SS7. These systems are commonly referred to xe2x80x9clegacy systems,xe2x80x9d a term that also includes other proprietary protocols such as ISDN_PRI, DPNSS, ISUP, TUP, NUP, H.323, and SIP. Due to the substantial investment in the legacy systems, it is desirable to keep the legacy systems in operation, yet still take advantage of the newer packet technologies.
These legacy systems, however, do not handle the protocols for the newer packet-switching networks, and, due to the age of many of the legacy systems, it is difficult and expensive to upgrade or replace the legacy systems to support the newer packet-switching protocols.
Accordingly, there exists a need for establishing and carrying voice calls that are originated or terminated by legacy systems over a packet-switching network. There is also a need for a way to seamlessly integrate legacy SS7-type systems and newer packet-switching networks.
Moreover, certain demographic trends are motivating telephone call carriers to integrate their systems with packet-switched networks. Certain countries are known to generate an above-average amount of long-distance telephone traffic. For example, residents of Israel are known to consume long-distance telephone services at a rate far greater than the average of residents in other industrialized nations. Long-distance telephone services carried over the PSTN are expensive. Voice calls carried over the globally accessible packet-switched network known as the Internet, however, are generally free. Accordingly, local telephone companies and other call access providers in certain countries are acutely interested in finding ways to integrate the PSTN with the Internet. data. In some embodiments, the first coding unit and the second coding unit are symmetrical and capable of performing both originating and terminating functions, depending on the call direction at any particular moment.
In one mode of operation, the first signaling unit receives the signaling data for establishing the voice call, obtains a network address of the first coding unit in the packet-switching network, and directly or indirectly controls the second coding unit to establish a bearer channel with the first coding unit for carrying the voice data through the packet-switching network, based on the network address. In another mode of operation, the signaling unit communicates with a second signaling unit to indirectly control the second coding unit to establish a bearer channel.
Another aspect of the invention relates to a signaling apparatus and a method for establishing a voice call bearing voice data through a packet-switching network. Accordingly, the signaling apparatus receives signaling data for establishing the voice cal by a first coding unit and obtains a network address of the first coding unit within the packet-switching network. A second coding unit is controlled to establish a bearer channel with the first coding unit for carrying the voice data through the packet-switching network, based on the network address.
Still other objects and advantages of the invention will become readily apparent from the following detailed description, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are intended as illustrative and not as restrictive.
These needs, and other needs that will become apparent from the following description, are addressed by the present invention, which implements voice calls over a packet-switched network. As used herein, a xe2x80x9cvoice callxe2x80x9d refers to both the voice signaling necessary to establish and tear down a voice connection and the voice data borne over the voice connection. Voice data includes human voice as well as data embedded in a voice signal, such as modem data, and facsimile data. The voice signaling, associated with the voice data, can be embedded in the same channel as the voice data, time-division multiplexed with the voice data on the same physical line, or present on a separate channel from the voice data.
More specifically, mechanisms are provided for handing the Layer 3 voice signaling of a voice call by a signaling apparatus and the Layer 2 voice traffic of the voice call by coding units. The signaling apparatus implements signaling interworking and protocol conversion, if necessary, between the legacy systems and the packet-switching network. The coding units convert bearer voice traffic between legacy and packet formats and, in some configurations, groom and backhaul the signaling information for the voice to the signaling apparatus. By separating the processing for voice signaling from handling the voice data, a flexible solution for integrating with legacy systems is attained.
One aspect of the invention involves a telecommunications network that includes a packet-switching network, such as an IP, ATM, or frame relay network, at least two coding units coupled to the packet-switching network and to an originating node and a terminating node, respectively, and a signaling apparatus coupled to the coding units. The first of the two coding units is configured, among other things, to transmit its network address to the signaling apparatus and, in one embodiment, signaling data associated with the voice call. The second coding unit is controllable to establish a bearer channel with the first coding unit through the packet-switching network for the voice call